There’s long been a debate over exactly how many fish there are in the sea — especially cod. Cod has been overfished for decades and because of that, strict catch limits were put in place, particularly in the Gulf of Maine where cod were once plentiful.

Author Rowan Jacobsen recently volunteered on one of the research expeditions that the National Oceanic and Atmospheric Administration runs to count cod and other fish off the Northeast coast, to determine if fishing cod is as sustainable as fishermen say it is.

They didn’t find much cod, but they did find several other types of fish, including the intimidating monkfish, one of the “trash fish” species that sustainable fisheries advocates say consumers should be eating more of now that cod is depleted.

Rowan Jacobsen speaks with Here & Now’s Jeremy Hobson about his expedition out to sea.

“The real story from, what I’ve seen, is cod are pretty much done — you can just cross them off the list for the foreseeable future,” Jacobsen says. “But there’s a lot of other fish out there — and that’s actually one of the big things we need to do and kind of wrap our heads around, is switching the fish that we look for in a store or in a restaurant from the few that we are familiar with, like cod, to ones that we might not be familiar with, but are abundant and delicious.”

There has long been a debate about how many fish there are in the sea, especially cod, which scientists say is overfished but fishermen say is plentiful. The government has put strict catch limits in place for cod, but the law that sets those catch limits is up for re-authorization. And there is talk in Congress of reforming it. So scientists with the National Oceanic and Atmospheric Administration as busily counting fish on research expeditions in the Gulf of Maine to help set catch limits.

Author Rowan Jacobsen volunteered on one of the recent expeditions. He wrote the article "Counting Fish" for the current edition of Yankee magazine, and he joins us now from the studios of Vermont Public Radio in Burlington. Rowan, welcome.

ROWAN JACOBSEN: Thanks, Jeremy.

HOBSON: So are there enough cod or is there a shortage? What's the real story?

JACOBSEN: The real story from what I've seen is that cod are pretty much done. You can just cross them off the list for the foreseeable future.

HOBSON: Really? Done?

JACOBSEN: Done. We're at historical lows in the populations that we're seeing. We seem to be at a similar place to where the Canadian fishery was in '92 when they had a moratorium on their cod fishery. And despite that, their cod numbers have not come back up in, you know, 20, 20 plus years of no fishing.

HOBSON: But the fishermen would say - and they do say - they're catching hundreds of them at a time. So why the discrepancy there?

JACOBSEN: Yeah. You know, that was one thing that I really hadn't understood before I went out on this NOAA boat. There are certain spots in the gulf, kind of like hotspots, where cod will concentrate. And if you're fishing in that spot, you know, your nets are coming up with hundreds of cod in them. You think things are great. But it turns out that a significant amount of the cod in the Western Atlantic will concentrate at these spots. And once you catch them, not only do you get a false sense of what's out there, but you've also just scooped out quite a few of the remaining ones.

Based on the quotas that were set, NOAA expected cod to rebound, and it really hasn't rebounded nearly as quickly as they thought it had. So that's one of the big questions is why isn't cod coming back?

HOBSON: Well - and you've been looking into this. I wanted you to tell us about your expedition. You went out onto the Bigelow - a ship called the Bigelow. Tell us about what you did and what you found.

JACOBSEN: Since the '60s, NOAA has been doing these surveys in U.S. fishing waters where they very scientifically fish and count every single fish that they catch. And based on what they see in those numbers, they set the quotas for what fishermen are allowed to catch. And I found out that they actually take volunteers on these boats. There are certain things we can do and certain things we can't do. Like I was, you know, online 12 hours a day with this conveyor belt of fish coming at us. And we would be cutting open every fish, weighing every fish, measuring it, cutting open its stomach and documenting the prey species inside.

HOBSON: So what did you find? What kind of fish did you catch and count and what about the cod?

JACOBSEN: We found an amazing abundance of fish. It was actually, I guess kind of heart-warming in a way to be out there and see all this fish load after load day after day, although that was also a lot of work. But I guess that's the good news, is that even though cod - the quotas on cod are incredibly low and are going to be incredibly low for years to come, but there's a lot of other fish out there. And that's actually one of the big things we need to do and kind of wrap our heads around is switching the fish that we look for in a store or in a restaurant from the view that we are familiar with, like cod, to ones that we might not be familiar with but are abundant and delicious.

HOBSON: Well, how difficult will it be to do that? Because people do have a hard time going with things that they don't know, especially fish, which many people don't even like to eat at all. What should we be looking for in the supermarket or at a restaurant when we decide we want to have some fish?

JACOBSEN: You know, the big one that could actually make a real difference - and there's groups of chefs pushing this fish right now and hoping that they can make it into a market - is dogfish. When all the cod disappeared, dogfish, which are basically these two- to three-foot sharks, kind of rushed in to fill that niche in the ecosystem. So there are an unbelievable number of dogfish out there.

When I was out on the Bigelow, you know, our nets would just come in almost bursting with dogfish. And there's no market for this fish, because people just aren't used to eating it and they think it tastes bad. But now, it all gets shipped to England for fish and chips at a very, very cheap price.

(LAUGHTER)

JACOBSEN: Hence the vinegar on the fish and chips.

HOBSON: Ah, I see. So you're saying it wouldn't be tasty if you just filleted it with some olive oil.

JACOBSEN: If it is actually delicious. I've had it a few different ways from various chefs, and it's been fantastic. But what - if you don't get to it right away, it can get rancid pretty quickly.

HOBSON: What about a monk fish? You encountered a monk fish. Tell us what that looks like and what happened.

JACOBSEN: Monk fish are definitely the tastiest fish in the North Atlantic, I think. It sometimes gets called poor man's lobster, which now doesn't make sense because it's actually pricier than lobster at the moment, but - delicious fish, but also just a completely freaky fish. We cut a lot of monk fish. It's like a bear trap with a tail attached. It's just this huge jaw full of incredibly sharp teeth stretched wide open, and it just waits there for other fish to come along, and then it snaps down on them.

And one actually snapped down on the finger of my partner I was working with in the Bigelow because we thought it was dead. It was just playing possum on us, and it actually got his finger in its mouth and wouldn't let it go.

HOBSON: Yikes.

JACOBSEN: I took a knife, a fillet knife, and jammed, like, the handle into its mouth to try to pry the mouth open, and it actually ripped the knife away from me.

(LAUGHTER)

JACOBSEN: And then it was, like, slashing around the table with the knife blade poking out of its mouth.

HOBSON: Maybe that's why we haven't caught very many of those and eaten them over the years.

(LAUGHTER)

JACOBSEN: They're a little scary to work with.

HOBSON: At the end of all of this and your expedition and talking to researchers, are you optimistic that we will be able to reverse the trend here of over-fishing and destroying the populations of fish-like cod, or do you think that we'll be able to turn some kind of a corner?

JACOBSEN: I actually wound up being quite optimistic, partly it was because I got to see NOAA in action, you know, really up close, where they couldn't hide anything for many days. And it's worked - the Sustainable Fisheries Act, which basically tasked NOAA with taking every fish stock that was overfished and bringing it back up to sustainable levels, it's worked for about two-thirds of the species that we fish for with a few exceptions like cod. So the thing that's going to make it work is not pressuring the scientists to try to raise those quotas higher than they know they need to be.

HOBSON: And to eat more dog fish, I guess.

(LAUGHTER)

JACOBSEN: More dog fish, lots of lobster.

HOBSON: Rowan Jacobsen is the author of the book "A Geography of Oysters: The Connoisseur's Guide to Oyster Eating in North America." His article "Counting Fish" is in the current edition of Yankee magazine. We've got a link at hereandnow.org. Rowan, thanks so much.